Concurrently inserting to Redis

I have three elements consisting of 1 million, 2 million and 3 million ints respectively. I want to insert them to redis such that they all happen concurrently and the total execution time is not greater than the execution time of the 3 million ints. I tried using sync.Waitgroup but it doesn't speed up the execution. Here's my basic code.

package main
import (
"log"
"strconv"
"time"
"gopkg.in/redis.v5"
)
func main() {
oneMillion := makeRange(1, 1000000)
twoMillion := makeRange(1000001, 3000000)
threeMillion := makeRange(3000001, 6000000)
elements := [][]int{oneMillion, twoMillion, threeMillion}
client := redis.NewClient(&redis.Options{
Addr:         "localhost:6379",
Password:     "",
DB:           0,
DialTimeout:  60 * time.Second,
WriteTimeout: 60 * time.Second,
ReadTimeout:  60 * time.Second,
PoolTimeout:  60 * time.Second,
})
pipeline := client.Pipeline()
for _, elem := range elements {
for i := 0; i < len(elem); i++ {
key := "KEY:" + strconv.Itoa(elem[i])
val := "VAL:" + strconv.Itoa(elem[i])
cmd := pipeline.Set(key, val, 0)
if cmd.Err() != nil {
log.Fatal("cmd error: ", cmd.Err())
}
}
_, err := pipeline.Exec()
if err != nil {
log.Fatal("error: ", err)
}
}
}
func makeRange(min, max int) []int {
a := make([]int, max-min+1)
for i := range a {
a[i] = min + i
}
return a
}

More or less every operation on redis is atomic , i.e only one operation will be executing on the redis server at any given time. So in theory if you want to do say 3 million set operations on a redis server all those operations will happen serially.